In this paper, we present the design and implementation of a negotiation-based resource management system called Mercury. As the number of resources in Grids is increasing rapidly, selecting appropriate resources to execute tasks has become a crucial issue. The proposed system implements the Extended Contract Net Protocol (ECNP), which improves the standard bidding model by integrating a matchmaking technique. Our model addresses the issues of matchmaker overload and the lack of up-to-date resource state information in the original matchmaking model. To ensure that the system is user-friendly, we provide a web interface. By using the provided job templates, users can describe their jobs more easily, and service providers can deploy their services in the system in a simple manner. Furthermore, to improve the interoperability of the system, we adopt open standards, such as the WS-Agreement and JSDL protocols. Our experimental results demonstrate the scalability and efficiency of the system.